Buccaneer enthusiasts will be donning their finest eye patches and throwing planks across their backyard pools for an annual cult celebration tomorrow: International Talk Like a Pirate Day, an excuse for shenanigans that comes around every September 19.

Businesses are using the holiday as an excuse for promotions. Long John Silver’s is giving away free whitefish if you just say “Arrr!”, and Krispy Kreme will dole out a donut to anyone yakking like a scoundrel on the high seas. Radio station DJs have promised to broadcast in pirate-ese. And Mango, a company that produces language-learning software, has put together an elaborate tutorial to help you “parley” in “perfect Pirate” for the occasion. You can even find out your pirate name using this pirate name generator. All of which raises the question of what, exactly, it means to talk like a pirate.

It’s easy to list off quick tips: say aaargh a lot, use ye instead of you and sound more British than a chimney sweep. But those tips have no relation to many of history’s pirates, aquatic robbers who could have been speaking Chinese as they set sail in the 1800s or Somali last Tuesday—without wearing so much as a tricorn hat. A swashbuckler isn’t even a pirate per se, just someone who swashes (lashes with a sword) at someone’s buckler (a small round shield).

Our modern impression of pirate speech, with all its yo-ho-ho-ing and timber shivering, was largely born from books like Robert Louis Stevenson’s Treasure Island and Hollywood films like Robert Newton’s 1950 adaptation of that novel. While there’s talk of captains letting out “inarticulate growls” as far back as Sir Walter Scott’s 1822 novel The Pirate, scholars haven’t found the same hard evidence in historical records. Still, the pop culture caricature has some links to history. Here are a few annotated tips to help you earn a breakfast treat in true pirate fashion tomorrow:

Use me when you would have used my.

Much like using ye—as in “ye be takin’ me cup o’ grog at yer own peril”—this imitates pronoun usage from early modern times, says Mark Hanna, a history professor at the University of California at San Diego who specializes in marauders. Bad grammar from that era, like using me instead of my, suggests that the speaker is lower class, and aristocrats were hardly regulars on the pirate circuit. Though, Hanna notes, captains would adopt language used by those above their rank in an attempt to assert authority over unruly crews.

Don’t be afraid to slur your words.

One truth about pirates, Hanna says, is that they were often deep in their cups, though that wasn’t necessarily because pirates just loved the taste of rum in their tum. Once anti-piracy laws in the late 1600s made it harder for them to spend their plunder and settle down on the mainland, the life became less appealing, he says—and the prospect of getting all you can drink was used to lure new recruits onboard.

Think nautical, matey.

Virginia Lunsford, a maritime historian at the U.S. Naval Academy, says the “golden age” of piracy spanned from about 1530 to 1730, an age of exploration when sailing was a major occupation. “Sailors had a distinctive way of speaking,” she says. “So pirates, as a subset of that demographic, would use nautical language.” Hence, while “Yo ho ho and a bottle of rum” is strictly a Stevenson invention, true pirates may have referred to compatriots as matey, greeted pillager pals by saying ahoy, gotten attention by yelling avast and exclaimed heave ho as they lifted anchor. (Note: Shiver me timbers, another phrase from fiction, is an oath synonymous withlet my wooden boat break to pieces, like a poetic sailor’s version of may the Lord strike me dead.)

Threaten people.

“Early modern people didn’t think piracy was silly and fun,” Lunsford says. “It was dangerous business.” So while taking part in tomorrow’s festivities is strictly a playful endeavor, violent threats will give your character a greater ring of truth. In The Pirate Primer, author George Choundas collects some menacing phrases, such as to die by inches (to suffer slow, prolonged torture), to hang from the yardarm (to swing from seagoing gallows), to give someone to the sharks (to throw him overboard) and to eat candles (to feed someone candles). Apparently pirates could be pretty literal, even if modern interpretations of them take a bit more license.

In honor of the big day, here’s a mashup of some of our favorite, pop-culture pirate moments:

This is an edition of Wednesday Words, a weekly feature on language. For the previous post, click here.